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Abstract:

A lighting device comprising a support for optical modules able to make a
rotation movement, comprising a first optical module able to generate a
light beam exhibiting a cutoff of the dipped beam type; a second optical
module able to generate a light beam exhibiting a substantially L-shaped
cutoff; the first optical module and the second optical module of the
first lighting device being disposed on the optical module support able
to make a rotation movement.

Claims:

1. A lighting device comprising a support for optical modules able to make
a rotation movement on an approximately vertical axis wherein said
lighting device comprises:a first optical module able to generate a light
beam exhibiting a cutoff of the dipped beam type;a second optical module
able to generate a light beam exhibiting a substantially L-shaped cutoff,
with a roughly horizontal first part, which is interrupted by a rise
ranging between 45.degree. and 135.degree. relative to said roughly
horizontal first part of the cutoff in question, said roughly horizontal
first part of the cutoff in question extending either towards the right
or towards the left of said rise;the first optical module and the second
optical module being disposed on the optical module support able to make
a rotation movement.

2. The lighting device according to claim 1, wherein said lighting device
further comprises a third optical module able to generate a light beam
with flat cutoff.

3. The lighting device according to claim 1, wherein said first optical
module, said second optical module and/or the third optical module
comprise at least one light source of the light-emitting diode type.

4. The lighting device according to claim 1, wherein said first optical
module comprises a single light-emitting diode.

5. The lighting device according to claim 1, wherein said second optical
module comprises a single light-emitting diode.

6. The lighting device according to claim 1, wherein said lighting device
comprises a third optical module able to generate a light beam with flat
cutoff and comprising a single light-emitting diode.

7. The lighting device according to claim 1, wherein said lighting device
comprises a third optical module able to generate a light beam with flat
cutoff and comprising at least two light-emitting diodes.

8. A set of lighting devices made up of a first lighting device and a
second lighting device, wherein said first lighting device is a lighting
device according to claim 1, and in that the second lighting device is a
second lighting device according to claim 1, the second optical module of
the first lighting device exhibiting a substantially L-shaped cutoff, the
horizontal part of which extends towards the right, and the second
optical module of the second lighting device exhibiting a substantially
L-shaped cutoff, the horizontal part of which extends towards the left.

9. The set of lighting devices according to claim 8, wherein said first
lighting device is a first motor vehicle headlight and said second
lighting device is a second motor vehicle headlight.

10. A method for automatically adapting a light beam generated by a set of
lighting devices according to claim 8, of a first motor vehicle running
along a road, said method comprising the steps of:detecting the presence
of at least one second vehicle, being followed or passed, not to be
dazzled;possibly determining a position of the at least one second
vehicle on the road;wherein said method comprises the following
additional steps:generating a selective light beam by means of a second
optical module of a first lighting device and a second optical module of
a second lighting device, the optical module of the first lighting device
generating a light beam exhibiting a substantially L-shaped cutoff, the
horizontal part of which extends towards the right, and the optical
module of the second lighting device generating a light beam exhibiting a
substantially L-shaped cutoff, the horizontal part of which extends
towards the left, so that the difference between the two vertical rises
of the cutoff lines of these two light beams creates a shadow zone in the
selective beam;positioning the shadow zone on the position of the at
least one second vehicle.

11. The method for automatically adapting a light beam according to claim
10, wherein said method comprises an additional step of superimposing,
onto the selective light beam, a light beam of the dipped beam type,
generated by the first optical module of the second lighting device on a
road with right-hand traffic, or of the first lighting device on a road
with left-hand traffic.

12. The method for automatically adapting a light beam according to claim
11, wherein said light beam of the dipped beam type is generated by a
light-emitting diode, the intensity level of which is determined by at
least one parameter, said parameter being:temperature information of said
first optical module and/or of the second optical module; and/orrange
correction information.

13. A motor vehicle comprising the set of lighting devices according to
claim 8.

14. The lighting device according to claim 2, wherein said first optical
module, said second optical module and/or the third optical module
comprise at least one light source of the light-emitting diode type.

15. The lighting device according to claim 2, wherein said first optical
module comprises a single light-emitting diode.

16. The lighting device according to claim 3, wherein said first optical
module comprises a single light-emitting diode.

17. The lighting device according to claim 2, wherein said second optical
module comprises a single light-emitting diode.

18. The lighting device according to claim 3, wherein said second optical
module comprises a single light-emitting diode.

19. The lighting device according to claim 4, wherein said second optical
module comprises a single light-emitting diode.

20. The lighting device according to claim 2, wherein said lighting device
comprises a third optical module able to generate a light beam with flat
cutoff and comprising a single light-emitting diode.

21. A method for automatically adapting a light beam generated by a set of
lighting devices according to claim 9, of a first motor vehicle running
along a road, said method comprising the steps of:detecting the presence
of at least one second vehicle, being followed or passed, not to be
dazzled;possibly determining a position of the at least one second
vehicle on the road;wherein said method comprises the following
additional steps:generating a selective light beam by means of a second
optical module of a first lighting device and a second optical module of
a second lighting device, the optical module of the first lighting device
generating a light beam exhibiting a substantially L-shaped cutoff, the
horizontal part of which extends towards the right, and the optical
module of the second lighting device generating a light beam exhibiting a
substantially L-shaped cutoff, the horizontal part of which extends
towards the left, so that the difference between the two vertical rises
of the cutoff lines of these two light beams creates a shadow zone in the
selective beam;positioning the shadow zone on the position of the at
least one second vehicle.

22. A motor vehicle comprising the set of lighting devices according to
claim 9.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application claims priority to French Application No. 0953827
filed Jun. 10, 2009, which application is incorporated herein by
reference and made a part hereof.

BACKGROUND OF THE INVENTION

[0002]1. Field of the Invention

[0003]The object of the present invention is a set of lighting devices
with light-emitting diodes, the acronym for which is LEDs, able to
generate an adaptive light beam. A lighting device, generally, is an
optical unit able to generate a light beam, based on one optical module
or several optical modules, and intended to be integrated in a headlight
device.

[0004]2. Description of the Related Art

[0005]The field of the invention is in general terms that of motor vehicle
headlights. In this field, various types of conventional headlights are
known, among which there are primarily:

[0006]side lights with low intensity and range;

[0007]low or dipped beam lights, of higher intensity and a range on the
road of around 80 meters, which are used essentially at night and where
the distribution of the light beam is such that it makes it possible not
to dazzle the driver of a vehicle being passed; the light beams of the
dipped beam type differ with the type of traffic, on the left or on the
right, in which they are used;

[0008]high beam lights of the long range type where the area of vision on
the road is around 600 meters, and which must be switched off when
passing another vehicle in order not to dazzle its driver;

[0009]fog lights; and

[0010]a type of improved headlight, referred to as dual function, which
combines the functions of dipped beam lights and high beam lights.

[0011]The conventional lighting devices that have just been mentioned,
more particularly those that are used as dipped beams, produce light
beams that are open to improvement when they are used under certain
conditions. Thus, for example, when a vehicle is entering a bend, the
headlights continue to illuminate straight in front of them whereas it
would be more judicious to orient the light beams in the direction of the
bend being taken. This is why, in addition to the conventional main
headlight functions, particularly dipped beam and main beam, various
improvements have gradually appeared.

[0012]Thus, elaborate functions have been seen, referred to as advanced
functions, or AFS ("Advanced Front lighting System" in English meaning
advanced front lighting system), among which there are also found
particularly, directly relating to the invention, a so-called DBL
function ("Dynamic Bending Light" in English meaning movable bending
light, called "code virage" in French), which produces an orientable
headlight, also referred to as a movable beam lighting device: such a
lighting device is able to modify the orientation of a light beam
produced by a lighting device so that, when the vehicle is entering a
bend, the road is illuminated in an optimum fashion, following the
geometry of the road.

[0013]In order to fulfill such a function, a first known technique
consists of making the global beam of the lighting device movable by
virtue of an actuator controlling the pivoting, at least partial, of the
lighting device according to information coming from the vehicle, for
example by means of a steering wheel angle sensor.

[0014]For all the headlights and side lights that have just been
mentioned, conventionally, light sources of the halogen lamp or discharge
lamp type are used. But for a few years now automotive equipment
suppliers have proposed the use of light-emitting diodes, also called
LEDs; this use for example relates to indicator lights or rear lights.

[0015]Light-emitting diodes offer a certain number of advantages. First of
all, for a long time, it has been known that this type of diode does not
radiate omni-directionally but radiates in a half space opposite to the
substrate that supports the p-n junction of the diode in question; thus,
by using a more directive radiation than halogen or discharge lamps, the
quantity of energy lost is less. Next these diodes were recently improved
in terms of radiation intensity. In addition the diodes emit radiation,
for a long time in the red range, but now also particularly in white and
orange, which increases their field of possible uses. The quantity of
heat that they give off is relatively limited but a certain number of
constraints, relating to the dissipation of heat, remains high in the
case of power LEDs. Lastly, LEDs consume less energy, even at equal
intensity of radiation, than discharge lamps or halogen lamps; they are
compact and their particular shape offers novel possibilities for
producing and arranging the complex surfaces that are associated with
them, particularly when arranging them on electronic media of the
flexible type.

[0016]In addition, with a general aim of making driving more comfortable
in terms of visibility, dual function headlight devices are used; in the
dual function optical modules of these headlight devices, the dipped beam
function automatically switches to the high beam function and vice versa,
the switching being dependent on the traffic conditions. With vehicles
equipped with such dual function modules, the procedure starts by
searching for the presence of a vehicle liable to be dazzled by using the
high beam function. If no vehicle is detected, the high beam function is
automatically activated. As soon as the presence of a vehicle is
detected, the high beam function is automatically de-activated and the
vehicle equipped with the dual function headlight again projects a light
beam of the dipped beam type.

[0017]In practice the threshold value above which the absence of a
detected vehicle authorizes switching over to the high beam function is
roughly 600 metres. As soon as a vehicle is detected at less than 600
meters from the equipped vehicle, it is the dipped beam function which is
activated. However this function only ensures satisfactory lighting to a
distance of about 80 meters in the central section of the road, and 150
meters on the verges of the road along which the vehicle is travelling
(that is to say the right verge with respect to right-hand traffic); the
lighting thus being projected primarily on the right side of the road in
the case of right-hand traffic, the left side of the road is
substantially less illuminated. Thus, there exists many traffic
configurations, in which the first vehicle liable to be dazzled is
located more than 100 meters and less than 600 meters away from the
equipped vehicle, for which the road lighting could be optimized, however
without dazzling the driver of any another vehicle.

[0018]Thus, various solutions are proposed allowing the range of the beam
to be adapted according to an estimated distance at which the vehicle
being passed or followed is situated. Progressive light beams are then
spoken of. Although these solutions may be satisfactory in terms of
optimizing the range of the light beam, this is not the case if the side
lighting of the road that is proposed is considered.

[0019]Thus, in the state of the art, solutions to cut off a global light
beam emitted by a vehicle in various adjacent angular portions, each
portion corresponding to an angular segment of the global beam are also
proposed. Therefore, if the vehicle being passed or followed is present
in a portion considered, an optimized global light beam would consist in
rendering only the portion considered of the global light beam not
dazzling. Selective light beams are then spoken of. A non-dazzling
portion means an angular segment of the global light beam in which the
beam is concentrated only under the horizontal when it reaches, or before
reaching, the vehicle being followed or passed.

[0020]However solutions proposed in the state of the art for producing
selective light beams in lighting devices also able to generate a light
beam of the dipped beam type use all of the mechanical solutions
including movable masks, producing variable cutoff lines depending on
their positioning. Such devices, which are frequently in demand,
encounter problems of reliability, particularly over the lifespan of the
lighting device.

SUMMARY OF THE INVENTION

[0021]It is an aim of the invention to improve the reliability of lighting
devices generating beams with variable cutoff lines.

[0022]According to one object of this invention, based on lighting devices
offering DBL functionality and equipped with LEDs, a set of lighting
devices able to generate, depending on the traffic conditions, a powerful
selective light beam, which is unencumbered by the presence of a system
of masks with all the risks of reliability and bulk, is proposed.
Advantageously, in one particular embodiment of the invention, it is also
proposed to generate the selective light beam progressively. To this end
it is intended, notably, on the movable part of at least one of the
lighting devices constituting the set of lighting devices according to
the invention, to arrange at least one first light source of the LED type
and a second light source of the LED type, each able to produce a
particular elementary beam with a particular cutoff, the fusion of the
various elementary beams generated allowing a selective beam to be
obtained based on lighting devices that are simplified in terms of
physical bulk.

[0023]The invention more particularly relates to a lighting device
comprising an optical module support able to make a rotation movement on
an approximately vertical axis, the lighting device comprising:

[0024]a first optical module able to generate a light beam exhibiting a
cutoff of the dipped beam type;

[0025]a second optical module able to substantially generate a light beam
exhibiting an L-shaped cutoff, with a roughly horizontal first part,
which is interrupted by a rise ranging between 45° and 135°
relative to the roughly horizontal part of the cutoff in question, the
horizontal part of the cutoff in question extending either towards the
right, or towards the left of the rise; and

[0026]the first optical module and the second optical module being
disposed on the optical module support able to make a rotation movement.

[0027]This embodiment makes it possible to be unencumbered by movable
masks in order to produce a lighting device generating at the same time a
beam comprising a cutoff of the dipped beam type and a beam with an
L-shaped cutoff, the cutoff able to be used in the context of a selective
beam. Thus, these lighting devices will be more reliable. In addition
movable masks are very bulky, complicating the production of the lighting
device in question. The devices according to the present invention
therefore are less expensive.

[0028]The lighting devices according to the invention, in addition to the
principal features stated in the preceding paragraph, can also exhibit
one or more of the following supplementary features; any combination of
these supplementary features, insofar as they do not mutually exclude one
another, constitutes an advantageous exemplary embodiment of the
invention:

[0029]the lighting device according to the present invention comprises a
third optical module able to generate a light beam with flat cutoff;

[0030]the first optical module, the second optical module and/or the third
optical module comprise at least one light source of the light-emitting
diode type;

[0031]the first optical module comprises a single light-emitting diode;

[0032]the second optical module comprises a single light-emitting diode;

[0033]the third optical module able to generate a light beam with flat
cutoff comprises a single light-emitting diode;

[0034]the third optical module able to generate a light beam with flat
cutoff comprises at least two light-emitting diodes.

[0035]The present invention also relates to a set of lighting devices
according to the present invention. Preferably this set of lighting
devices can also exhibit one or more of the following supplementary
features; any combination of these supplementary features, insofar as
they do not mutually exclude one another, constitutes an advantageous
exemplary embodiment of the invention:

[0036]this set consists of a first lighting device and a second lighting
device, which are lighting devices according to the present invention,
the second optical module of the first lighting device exhibiting a
substantially L-shaped cutoff, the horizontal part of which extends
towards the right, and the second optical module of the second lighting
device exhibiting a substantially L-shaped cutoff, the horizontal part of
which extends towards the left; and

[0037]the first lighting device is a first motor vehicle headlight and the
second lighting device is a second motor vehicle headlight.

[0038]The present invention also relates to a method for automatically
adapting a light beam generated by a set of lighting devices according to
the present invention, of a first motor vehicle running along a road,
this method comprising the steps of:

[0039]detecting the presence of at least one second vehicle, being
followed or passed not to be dazzled;

[0040]possibly determining a position of the second vehicle on the road;
the method comprising the additional steps of:

[0041]generating a selective light beam by means of the second optical
module of the first lighting device and the second optical module of the
second lighting device, the optical module of the first lighting device
generating a light beam exhibiting a substantially L-shaped cutoff, the
horizontal part of which extends towards the right, and the optical
module of the second lighting device generating a light beam exhibiting a
substantially L-shaped cutoff, the horizontal part of which extends
towards the left, so that the difference between the two vertical rises
of the cutoff lines of these two light beams creates a shadow zone in the
selective beam;

[0042]positioning the shadow zone on the position of the second vehicle.

[0043]This method, in addition to the principal features stated in the
preceding paragraph, can also exhibit one or more of the following
supplementary features; any combination of these supplementary features,
insofar as they do not mutually exclude one another, constitutes an
advantageous exemplary embodiment of the invention:

[0044]it comprises an additional step of superimposing, onto the selective
light beam, a light beam of the dipped beam type, generated by the first
optical module of the second lighting device, on a road with right-hand
traffic or of the first lighting device, on a road with left-hand
traffic.

[0045]the light beam of the dipped beam type is generated by a
light-emitting diode, the intensity level of which is determined by at
least one parameter, the parameter being:

[0046]temperature information of the first optical module and/or of the
second optical module; and/or

[0047]range correction information.

[0048]The present invention also relates to a motor vehicle comprising the
set of lighting devices according to the invention.

[0049]The invention in its various applications will be understood better
from reading the following description and an examination of the figures
which accompany it.

[0050]These are presented only by way of indication and are in no way
limitative of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0051]FIG. 1 is various examples of light beams generated by the set of
devices according to the invention;

[0052]FIG. 2 is a schematic representation, in cross section, of an
example of the optical module according to the invention;

[0053]FIG. 3 is a schematic representation, in perspective, of an example
of the optical module according to the invention;

[0054]FIG. 4 is a partial representation of one of the lighting devices
able to be used in an exemplary embodiment of the set of lighting devices
according to the invention; and

[0055]FIGS. 5 and 6 are various combinations of luminous beams likely to
be found in the sets of lighting devices according to the invention are
illustrated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056]The elements appearing on various figures, unless otherwise
specified, have kept the same reference. Various designations of
position, for example "below", "above", "vertical", "higher", and "lower"
should be considered under conditions of normal road traffic or use of
the set of lighting devices according to the invention, when the latter
is installed to function on a motor vehicle. The object of the invention
is described for a set of lighting devices equipping a vehicle adapted to
right-hand traffic conditions. The object of the invention is obviously
directly transposable to the left in left-hand traffic conditions.

[0057]On FIG. 1, various examples of light beams able to be generated by a
first lighting device and a second lighting device of the set according
to the invention are illustrated.

[0058]Thus, the first lighting device, which here is a left-hand front
lighting device, generates:

[0059]a first elementary light beam 103, exhibiting a cutoff 104
corresponding to a conventional dipped beam for driving on the right;

[0067]Superimposition of the three elementary beams which have just been
quoted results in a right-hand light beam 207.

[0068]L-shaped cutoff means a cutoff line with a roughly horizontal first
part, which is interrupted by a substantially vertical rise, that is to
say ranging between 45° and 135°, of the cutoff in
question, the horizontal part of the cutoff in question extending either
towards the right or towards the left of the substantially vertical rise.
Thus, the cutoff lines 106 and 206 mentioned above, in one particular
example, can be symmetrical to each other. In other exemplary embodiments
they are not symmetrical to each other. In the example illustrated, the
second elementary light beam 105 of the left-hand lighting device
exhibits an L-shaped cutoff, the horizontal part of which is towards the
right in the elementary beam 105, whereas the second elementary light
beam 205 of the right-hand lighting device exhibits an L-shaped cutoff,
the horizontal part of which is towards the left in the elementary beam
205.

[0069]On the various light beams illustrated, the optical axis of the
optical module generating the elementary beam in question is marked by
the reference O. The various light beams which have just been mentioned
are advantageously generated by distinct optical modules disposed inside
each of the two lighting devices in question, the nth elementary beam
being produced by an nth optical module. Optical module, in the present
application, means an optical system comprising at least one light
source, possibly disposed in a reflector, sometimes on a complex surface,
and possibly associated with one or more dioptrical elements of the
reflector type or lens face type.

[0070]According to one essential feature of the invention, as illustrated
on FIG. 4, it is proposed, inside at least one of the two lighting
devices of the set according to the invention, to mount the first optical
module, reference 403, and the second optical module, reference 404, on a
support 401 able to make a rotation movement on an approximately vertical
axis of rotation 402. Thus, the first and second elementary light beams,
due to the rotation of support 401 about axis 402, are able to move
roughly horizontally, as illustrated by a first arrow 108 and a second
arrow 208 shown on FIG. 1. In an advantageous embodiment the first and
second optical modules are mounted on such a support in the first
lighting device and in the second lighting device.

[0071]Activation of the second optical modules of the two lighting devices
makes it possible to generate a selective light beam: once the position
of a vehicle 109, being passed or followed, is determined by known
techniques, utilizing for example notably a camera and image-processing
algorithms, support 401 rotates so as to leave, in a global light beam
111, a space that is not illuminated above the horizon only around an
angular portion 110 containing the vehicle 109.

[0072]According to an alternative embodiment, activation of one of the
first optical modules makes it possible to advantageously generate a
progressive light beam by reinforcing the luminous intensity around a
certain zone 113 of the global light beam 111, the zone 113 corresponding
to the luminous coverage of the elementary light beam 203 corresponding
to the conventional dipped beam. In the example illustrated on FIG. 1,
the vehicle equipped with the devices according to the present invention
is travelling on the right. Consequently in the lighting device located
on the right, the first module is switched on at the same time as the
second module and the first module generates a first elementary light
beam 203, exhibiting a cutoff 204 corresponding to a conventional dipped
beam for driving on the right which, being superimposed onto the second
elementary beam 205, results in reinforcing the lighting in the part
located on the right of the horizontal part of the cutoff of the first
elementary beam 205, thus reinforcing the lighting on the verges and on
the right of the detected vehicle. On the other hand the first module of
the left-hand lighting device is switched off and the second module is
switched on.

[0073]In an advantageous example the light-emitting diode of the third
optical module is switched on progressively, according to a control
strategy determined beforehand. Thus, for example, in order to determine
the luminous intensity of the diode, the control strategy takes into
account at least one of the following parameters in order to determine
the luminous intensity of the diode:

[0074]temperature information of the optical module in which the diode is
disposed; the intensity of the diode for example can thus be reduced if
too a high temperature is detected, near to the acceptable limit for
operation of the diode, in order to cause a drop in the temperature;

[0075]range correction information: by determining the position of a
vehicle being followed or passed, the range correction can be used to
raise the light beam generated by the set of lighting devices according
to the invention; advantageously the intensity of the diode in question
can vary as a function of the range correction information provided the
higher the range correction, the higher the intensity of the diode in
question.

[0076]In an advantageous embodiment, in order to improve the progressive
character of the global light beam, vertical displacement means 112 of
the global light beam 111 are used. These means can consist of any
mechanism making it possible to move the global light beam vertically,
particularly the pitch angle correction or range correction mechanism.

[0077]Advantageously, in the invention, the light sources used are of the
LED type. Thus, compared to light sources of the discharge lamp type,
great amplitude is provided in the variation of the intensity of each
elementary light beam generated by an optical module comprising at least
one LED, and particularly of the second and third elementary light beams.
The variation in luminous intensity thus produced by each optical module
increases performance in terms of progressive generation of the light
beam.

[0078]In the examples illustrated on FIG. 1, it is also possible by means
of the device to obtain a beam of the conventional dipped beam type by
switching off the second modules and by switching on the first. With the
lighting devices illustrated on FIG. 1, the dipped beam would be
obtained, for the left-hand lighting device, by superimposition of the
first elementary beam 103 and the third elementary beam 101 and, for the
right-hand lighting device, by superimposition of the first elementary
beam 203 and the third elementary beam 201. The dipped beam generated by
the set of lighting devices of the vehicle will result from the fusion of
these four elementary beams 101, 103, 201 and 203.

[0079]In an advantageous exemplary embodiment of the system according to
the invention, notably in terms of bulk and production costs, the optical
modules used correspond to the optical module 1 illustrated on FIGS. 2
and 3.

[0080]Optical module 1 comprises:

[0081]a first reflector 2;

[0082]a second reflector 3;

[0083]a third reflector 4; and

[0084]a light source 5.

[0085]First reflector 2 is a reflector of the elliptical type having:

[0086]two focuses F1 and F2;

[0087]an optical axis A1; and

[0088]a substantially elliptical reflective surface 6.

[0089]The approximately elliptical surface 6 of revolution is implemented
in the shape of an angular segment and extends in the half space situated
above an axial plane perpendicular to the plane of the sheet and
comprising the optical axis A1. As a first approximation, surface 6 is
semi-ellipsoidal.

[0090]However, it should be noted that surface 6 may not be perfectly
elliptical and can have several profiles specifically designed to
optimize luminous distribution in the light beam generated by module 1.
This implies that first reflector 2 does not have a perfect surface of
revolution.

[0091]The light source 5 is arranged substantially in line with the first
focus F1 of first reflector 2.

[0092]As stated above, advantageously, the light source 5 is a
light-emitting diode which emits most of its luminous energy towards the
reflective inner face of the approximately elliptical surface 6.

[0093]Second reflector 3 comprises:

[0094]a focus roughly in line with the second focus F2 of first reflector
2;

[0095]an optical axis A2; and

[0096]a reflective surface 7.

[0097]The optical axis A2 is substantially parallel to the longitudinal
axis of a vehicle, not illustrated, and equipped with the lighting module
1.

[0098]Optical axis A1 forms an angle α with the optical axis A2. In
the example illustrated angle α is equal to 90°; in other
exemplary embodiments however, a different angle is possible.

[0099]According to a first embodiment, reflective surface 7 has a
substantially parabolic shape, the axis of the parabola being the optical
axis A2.

[0100]Third reflector 4, so called folder, is situated between first
reflector 2 and second reflector 3 and comprises at least one higher
reflective surface 8 and a front end edge 9, known as cutoff edge.

[0101]The cutoff edge 9 is arranged in the vicinity of the second focus F2
of first reflector 2.

[0102]The operating principle of the optical module 1 is as follows:

[0103]For this purpose we will consider three luminous rays R1, R2 and R3
emanating from the light source 5.

[0104]As the light source 5 is arranged in line with the first focus F1 of
first reflector 2, the major part of the rays emitted by source 5, after
being reflected on inner face of surface 6, is returned towards the
second focus F2 or in the vicinity of the latter. This is the case of ray
R1 which passes along the cutoff edge 9. R1 is then reflected on surface
7 of second reflector 3 along a direction substantially parallel to the
optical axis A2 of second reflector 3.

[0105]However other rays, after being reflected on inner face of surface
6, can reflect on surface 8 of third reflector 4; this is the case of R2.
R2 will then again be reflected on parabolic surface 7 and this
reflection will be directed towards the left in the plane of FIG. 1. Ray
R2 is thus emitted under the cutoff in the light beam. Without the
reflection of R2 on surface 8, ray R2 would have been unacceptable
(because above the cutoff).

[0106]Other rays, of the type R3, can pass above edge 9. In such a case,
ray R3 is also emitted under the cutoff in the light beam.

[0107]An advantage of the optical module 1 is thus that it does not
eclipse a major part of the luminous rays emitted by source 5, as is the
case with a conventional lighting module comprising a mask.

[0108]Reflective surface 8 makes it possible "to fold" the images of the
light source 5 which are reflected by elliptical surface 6 of first
reflector 2 of the second focus F2.

[0109]The "fold" created by this "folding" of images contributes to the
formation of a clean cutoff in the light beam reflected by second
reflector 3.

[0110]Angle α is selected and optimized by using the property of the
diodes to emit only in a half space so that first reflector 2 does not
intercept part of the flux reflected by second reflector 3. The angle
chosen here is equal to 90° but this angle may also be higher than
90° in order to obtain a more compact module while making it
possible that first reflector 2 does not to intercept part of the flux
reflected by second reflector 3.

[0111]In such optical modules it is the shape of the cutoff edge 9 which
determines the shape of the cutoff line of the elementary beam generated
by the optical module in question. For example, by choosing a cutoff edge
of the type shown on FIG. 3, where the folder comprises two upper
surfaces comprised in planes with an angle of 15°, a cutoff
allowing the conventional European dipped beam function to be fulfilled
is obtained. To achieve an L-shaped cutoff, the cutoff edge must exhibit
the shape of an "L", with a first part and a second part between them
forming an angle close to 90°, more generally ranging between
45° and 135°.

[0112]In the case of a third module, intended to form an elementary beam
101, the folder has a surface without interruptions, this surface
allowing the formation of a flat horizontal cutoff.

[0113]On FIGS. 5 and 6 various combinations of light beams in right-hand
traffic likely to occur at the time of various alternatives of the
inventive method are illustrated.

[0114]Thus, on FIG. 5, a first alternative 501 corresponds to the
combination of the variable beams detailed in the description of FIG. 1.
Array 517 of elementary beams which can be generated by the left-hand
lighting device is illustrated on the left and array 527 of the
elementary beams which can be generated by the right-hand lighting device
is illustrated on the right on FIG. 5. As seen previously, according to
an alternative method the first elementary beams 103 and 203 of two
lighting devices according to the present invention can be generated at
the same time in order to produce a conventional dipped beam. As
described on FIG. 1, the second elementary beams 105 and 205 can be
combined in order to produce a selective beam, possibly combining the
first elementary beam 203 on the right-hand side to improve the range of
the selective beam and thus render it progressive.

[0115]According to a second alternative 502 it is proposed that a
left-hand headlight device 503 is produced equipped with a first optical
module and a second optical module, according to the terminology employed
above, generating a light beam 505 of the dipped beam type for left-hand
traffic conditions and a light beam 506 with an L-shaped cutoff, with the
horizontal part on the right. In a symmetrical way, it is proposed that a
right-hand headlight device 504 is produced equipped with a first optical
module and a second optical module, according to the terminology employed
above, generating a light beam 507 of the dipped beam type for right-hand
traffic conditions and a light beam 508 with an L-shaped cutoff, with the
horizontal part on the left respectively. With such light beams,
particularly a selective light beam, the luminous intensity of which can
be reinforced on the right as well as on the left of a non-illuminated
central zone, may be generated by controlled and staggered activation of
the diodes equipping the second optical modules, creating beams of the
dipped type.

[0116]According to a third alternative, not illustrated, the left-hand
lighting device comprises three lighting modules generating elementary
beams, such as beams 103, 105 and 505 respectively, and the right-hand
lighting device comprises three lighting modules generating elementary
beams, such as beams 203, 508 respectively and a beam identical to beam
505. Thus, according to the regulations in the country in which the
vehicle is driven, a dipped beam can be generated for left-hand traffic
or a dipped beam for right-hand traffic, as well as a selective beam as
described above, reinforced on either side by the shadow zone according
to the desired range.

[0117]While the method herein described, and the forms of apparatus for
carrying this method into effect, constitute preferred embodiments of
this invention, it is to be understood that the invention is not limited
to this precise method and forms of apparatus, and that changes may be
made in either without departing from the scope of the invention, which
is defined in the appended claims.